It’s 2017, and the problem appears to still be there. In fact, it’s even worse, since Dropbox has to notify me every time I take a screenshot (even though I turned off notifications), and Windows chooses to notify me when Windows Defender has not detected any threats.

One very ugly fix is to go into System Sounds and disable the Windows | Notification entry. But I actually want notification sounds, I just don’t want them blasting at full volume.

So, here is my ugly hack: I loaded the “Windows Notify System Generic.wav” file into Audacity, dropped the volume 20dB, and set that as my notification sound.